Quantifying the Impact Nitrogen and Phosphorus Levels have on the Growth of Algae in Canyon Ferry Lake.

Abstract

The presence of toxic algae blooms, caused by high nitrogen and phosphorus concentrations, is a problem for aquatic ecosystems. Canyon Ferry Lake on the Missouri River has been subject to algae blooms over the years due to rising nitrogen and phosphorus concentrations. The goal of this project was to determine the levels of nitrogen and phosphorus at which algae blooms occur. This project is a collaboration between the Montana Department of Environmental Quality, an introductory Chemistry class, and a senior level capstone research class. Samples from the Canyon Ferry Lake were collected and spiked with different concentrations of phosphates (dipotassium phosphate) and nitrates (sodium nitrate). The added nitrogen concentrations ranged from 0 to 5 ppm and the added phosphorus concentration ranged from 0 to 2 ppm. The nitrogen and phosphorus spiked Canyon Ferry Lake water samples were incubated for two weeks under a 12-hour illumination cycle. The chlorophyll a concentration, which is known to correlate to algae population, of the samples were then analyzed via high-performance liquid chromatography (HPLC) and steady state ultraviolet-visible (UV-Vis) spectroscopy. The largest algae growth was found with 1.5 ppm nitrogen and 0.6 ppm phosphorus added. The possible implications for these findings for the management of Canyon Ferry Lake aquatic ecosystem will be discussed.